Burnt Clay Research Articles

Application of burnt clay shale as pozzolan addition to lime mortar

Abstract Burnt Czech clay shale of different grain fineness is applied as a new pozzolan addition to lime mortar. Experimental results show that the new lime–pozzolan mortars have significantly better mechanical properties and frost resistance than the reference lime mortar. The fineness of burnt Czech clay shale is a very important parameter affecting the properties of lime–pozzolan mortars; the best results are achieved with an average particle size of 4 μm. In a comparison with a lime–metakaolin mortar of the same composition, the frost resistance of the new lime–pozzolan mortars is significantly better, the mechanical, fracture-mechanical, hygric and thermal properties are either comparable or slightly better. Therefore, it can be concluded that the burnt Czech clay shale has a good potential to be used in lime–pozzolan mortars for renovation of historical buildings.

PENURUNAN ION Fe DAN Mn AIR TANAH KOTA BANJARBARU MENGGUNAKAN TANAH LEMPUNG GAMBUT SEBAGAI ADSORBEN

Indonesia, particularly Kalimantan island has abundant source of clay peat (CP). CP found as soil grain which is composed by silicon-oxygen tetrahedral and aluminium-oxygen octahedral essential form of very fine mineral. CP has ability in color removal, reducing organic matter and heavy metals which are dissolved in water through adsorption process. This research investigated the influence of adsorbent from natural peat clay, physical activated natural peat clay and chemical activated natural peat clay with CP depth parameter (2, 3 and 4 meters from the soil surface) in adsorbing Fe and Mn from Banjarbaru groundwater. The chemical activation was done by contacting the clay peat with 0.25 M HCl , while the physical activation by burning clay peat in furnace with a temperature of 600 o C for 4 hours This research conducted by contacting the adsorbent with 1liter of water from Rambai well for 300 minutes. The results showed that the clay peat based on physical activation at a depth of 3 m gave the optimum conditions in reduction Fe, as shown from the values obtained was 0.27 mg/L, whereas chemical activation at a depth of 2 m could reduce Mn to be 0.081 mg/L.

Artificial pozzolanic cement pastes containing burnt clay with and without silica fume

Pozzolanic cement blends were prepared by the partial substitution of ordinary Portland cement (OPC) with different percentages of burnt clay (BC), Libyan clay fired at 700 °C, of 10, 20, and 30%. The pastes were made using an initial water/solid ratio of 0.30 by mass of each cement blend and hydrated for 1, 3, 7, 28, and 90 days. The pozzolanic OPC–BC blend containing 30% BC was also admixed with 2.5 and 5% silica fume (SF) to improve the physicomechanical characteristics. The hardened pozzolanic cement pastes were subjected to compressive strength and hydration kinetics tests. The results of compressive strength indicated slightly higher values for the paste made of OPC–BC blend containing 10% BC The results of DSC and XRD studies indicated the formation and later the stabilization of calcium silicates hydrates (CSH) and calcium aluminosilicate hydrates (C3ASH4 and C2ASH8) as the main hydration products in addition to free calcium hydroxide (CH). Scanning electron microscopic (SEM) examination revealed that the pozzolanic cement pastes made of OPC–BC mixes possesses a denser structure than that of the neat OPC paste. Furthermore, the addition of SF resulted in a further densification of the microstructure of the hardened OPC–BC–SF pastes; this was reflected on the observed improvement in the compressive strength values at all ages of hydration.

Physicochemical, Microstructural and Thermal Characteristics of Some Artificial Pozzolanic Cement Pastes Containing Burnt Clay with and without Silica Fume

Physicochemical, Microstructural and Thermal Characteristics of Some Artificial Pozzolanic Cement Pastes Containing Burnt Clay with and without Silica Fume

Engineering properties of cemented peat bricks

Housing is a great problem in today’s world and the world future. The most basic building material for infrastructure construction and housing is the usual brick or blocks. Conventional bricks, which are burnt clay, create environmental problems. The purpose for this study was undertaken on the production of peat; siliceous sand, composite cement and lime solid bricks to solve the economic problems of housing and construction building by utilizing local materials. The compressive strength, water absorption and density of these bricks were investigated. It was observed that these bricks had sufficient strength for their use in low cost housing development. Tests were also conducted to study the influence of curing type on the increase in strength and hardening of the bricks with time. Key words: Peat, PFA cement, lime, siliceous sand.

Properties of compressed lateritic soil stabilized with a burnt clay–lime binder: Effect of mixture components

In this study, a pozzolanic binder containing lime and a common thermally activated kaolinitic clay, at 750 °C, was formulated. The chemical, mineralogical and pozzolanic properties of raw materials were determined. The percentage of lime in the binder varies between 20% and 30%. The binder was used as a stabilizer in compressed lateritic soil in which water–solid (laterite and binder) and laterite–binder ratios vary, respectively, from 0.12 to 0.20 and 4 to 9. Sodium hydroxide (NaOH) was added as a chemical activator in the mixture. The NaOH–binder ratio varies from 0.02 to 0.04. The average effect of each component of the mixture on compressive strength, water absorption and apparent density of compressed laterite after 7 or 28 days of conservation at 40 ± 1 °C in an atmosphere saturated with water vapour was evaluated in a screening design of the “design in graeco – latin squares” type. It was observed that water–solid and laterite–binder ratios are the factors that influence more the properties of the products. Compressive strength increases up to a water–solid ratio of 0.16 then decreases for higher ratios. Compressive strength decreases with the increase of laterite–binder ratio. Water absorption decreases with the increase of water–solid ratio up to 0.16 then sharply increases for higher ratios. However, water absorption decreases slightly with the increase in the lime content of the binder and sodium hydroxide–binder ratio. The maximum apparent density is observed at water–solid ratio of 0.16. It increases when sodium hydroxide–binder and laterite–binder ratios increase.

Plant remains from an early Neolithic settlement at Moravany (eastern Slovakia)

This paper presents the results of the investigation of macroscopic plant remains from the early Neolithic site of Moravany, Slovakia, dated to the third quarter of the 6th millennium cal b.c., from which 141 samples of burnt clay were examined. The most abundant remains belonged to Triticum dicoccon. Two other cereals were found, T. monococcum and Hordeum vulgare. Fifty-five soil samples contained a few specimens of charred grains of T. dicoccon and diaspores of the wild plants Chenopodium album, Saponaria officinalis, Solanum nigrum and Bromus sp. Over 2,000 pieces of charcoal were examined, among which 14 plant taxa belonging to gymnosperms and angiosperms have been recognized. The most common were Quercus (oak), Fraxinus (ash) and Ulmus (elm). Archaeobotanical and chronological data demonstrate that a farming economy was practised in eastern Slovakia as early as the mid 6th millennium b.c. The trees identified from the charcoals reveal that typical early Atlantic woodland communities with a predominance of deciduous trees and shrubs constituted the environmental context of the first Neolithic settlers there. Wood of these taxa was used for construction and as fuel.

Relevance of magnetic properties for the characterisation of burnt clays and archaeological tiles

The archaeomagnetism of pottery, bricks and tiles is typically employed for dating inferences, yet the magnetic properties of ancient ceramics can also be convenient for their characterisation, to evaluate the technological conditions applied for their production (temperature, atmosphere, and duration of firing), as well as to distinguish groups of sherds having different provenance. In this work, the measurement of hysteresis loops has been applied and combined with colour survey to characterise the magnetic properties of burnt clays and archaeological tiles. Four calcareous and non-calcareous clays, along with seventeen tile fragments excavated from the sites of the ancient Roman towns of Pompeii and Gravina di Puglia, in Southern Italy, are examined. The ferrimagnetic character of the clays, in general, enhances with increasing firing temperatures until vitrification processes occur (900–1000 °C) dissolving iron oxides and dispersing the colour and magnetic properties they provide. High values of saturation magnetization are observed in clays with relevant calcareous content after firing above 900 °C, which results in the formation of Ca-silicates able to delay the onset of the vitrification processes. Magnetic properties of the tiles have been evaluated in terms of the high coercivity (i.e. mainly ferrimagnetic) or low coercivity behaviour (i.e. including relevant paramagnetic and superparamagnetic contributions). Enhanced ferrimagnetic character, mostly depending on the growth in number and volume of iron oxide particles, is associated with the development of an intense reddish hue.

Development and Performance Evaluation of Indigenously Made Cooling Chambers for Extending the Shelf Life of Mangoes and Sweet Oranges

A study was conducted to develop, construct and evaluate the performance of cooling chambers made from factory pressed burnt clay (structure-1), locally molded mud blocks (structure-2) and wood wall (structure-3) for extending the shelf life of mangoes and sweet oranges. It was observed that structure-1 significantly (p&#88040.05) registered low temperature and high relative humidity over structure-2 and structure-3. Significant lower physiological loss (p&#88040.05) in weight (PLW) was observed in commodities stored under structure-1 due to the low temperature and high RH probably arising from the low vapor pressure. Structure-2 registered significantly (p&#88040.05) low PLW as compared to structure-3 attributable to the differences in wall thickness. Total soluble solids increased as storage time progressed. The rate of increment, however, was significantly lower in mangoes stored under structure-1 as compared to the other chambers. The juice content of the commodities decreased over time irrespective of cooling chambers. The rate of reduction in juice content was, however; significantly lower in structure-1 than the other two. Keywords: Cooling-Chamber; Mango; Shelf-life; Sweet-Orange East African Journal of Sciences Vol. 1 (2) 2007: pp. 127-135

Potentiality of open burnt clay as an adsorbent for the removal of Congo red from aqueous solution

Open burnt clay was studied as a potential adsorbent for the adsorption of Congo red (a reactive dye) from aqueous solution. The effect of contact time, pH, adsorbent dosage and temperature were studied. It was observed that the amount of Congo red retained increase with decreasing pH and increasing initial concentration. Removal percentage at pH 2 and 3 are almost same. The adsorption capacity of regenerated burnt clay was showed more than 98 % recovery of the adsorption efficiency of initial virgin adsorbent. The equilibrium data were described well by both Langmuir and Freundlich isotherm model. The adsorption capacity of some natural adsorbents, namely rice husk, wood charcoal, tea waste etc. were also investigated and compared with that of open burnt clay.

Comparative Performance of Burnt Clay Bricks and Compressed Stabilized Earth Bricks and Blocks

"ENGINEER", established in 1973 by The Institution of Engineers, is a Journal for dissemination of Engineering knowledge, published quarterly.If you are interested in contributing an Original Technical Paper based on research by the author(s) (intended for Section I) or an Original Article of Professional or Technical interest related to Engineering. (Section II) to this journal please go through the publication checklist which can be downloaded from here.Cover DescriptionCover images show a few views of Stage II of the Central Expressway from Mirigama to Kurunegala. The Institution of Engineers Sri Lanka acknowledges the Road Development Authority (RDA) for the images.

Characteristic of paramagnetic centres in burnt clay and pottery by the EPR method

The samples of natural clay and pottery have been investigated by using electron paramagnetic resonance (EPR) method. Because of young age (100–5000 years old) of these materials and the presence of iron compounds the big doses (1–200 kGy) of irradiation have been used. The authors investigated whole material without quartz extracting from acid washing. In natural clay the EPR lines were observed which disappear after clay burning and they were also not present in EPR spectrum of pottery. After clay burning at temperatures similar to these at which pottery was burnt the spectra of clay became similar to pottery spectra. These EPR spectra have also similar hyperfine structure for which the g factors are equal g 1 = 2.0595 , g 2 = 2.0079 , and g 3 = 2.0018 for clay and g 1 = 2.0602 , g 2 = 2.0079 and g 3 = 2.0019 for pottery. For these lines the [ AlO 4 ] 0 centre in quartz was ascribed.

Analysis of the Sesquiterpenoids in Processed Atractylodis Rhizoma

In Asia, processed Atractylodis Rhizoma, the dried rhizome of Atractylodes ovata De Candolle (Compositae), is widely used as a tonic agent in herbal diets; stir-frying with soil is the most common processing method. In this study, we focused on determining variations in the function and concentrations of sesquiterpenoids in processed Atractylodis Rhizoma. Raw Atractylodis Rhizoma was processed by stir-frying it with different assistant substrates (i.e., red soil and burnt clay). The results indicated that there was less atractylon in stir-fried materials than in raw materials. However, there were higher levels of atractylenolides II and III in stir-fried materials than in raw materials. We also found that the heavy-metal content in burnt clay exceeded regulations set by the Taiwanese government. Moreover, commercial Atractylodis Rhizoma in Taiwan exhibited great differences in concentrations of the active components. In addition, atractylon showed stronger cytotoxicity than atractylenolides II and III in various cell lines. Therefore, we suggest that the toxic effects of atractylon are reduced following atractylon degradation to atractylenolides II and III. In conclusion, the toxicity of Atractylodis Rhizoma is reduced through processing.

A geophysical approach to buried site detection using down‐hole susceptibility and soil magnetic techniques

AbstractRecently developed down‐hole magnetic capabilities and laboratory soil magnetic techniques are combined in a geophysical approach to identify buried archaeological sites. Down‐hole magnetic susceptibility measurements are used to locate palaeosols and soil magnetic studies are applied to evaluate whether an associated human occupation is likely. This geophysical approach has the potential to locate and explore buried archaeological deposits across varied environments in a cost‐effective, efficient, and relatively non‐invasive manner.This approach was developed and tested on sites in Minnesota and North Dakota, USA. Prototype Bartington Instruments MS2H down‐hole sensors allowed identification of major stratigraphical units, buried occupation layers and non‐cultural palaeosols at these sites. Buried soils correlated with enhanced susceptibilities.Buried cultural soils produced, in some cases, a signal over twice the magnitude of non‐archaeological palaeosols. Although this magnitude shift suggested a possible avenue for determining if ancient land surfaces had been occupied by humans, laboratory soil magnetic techniques, which allow an understanding of changes in composition, concentration and/or grain size of the magnetic carrier that produce this contrast in magnitude, were found to be much more effective in making this determination. These soil magnetic tests were applied to sediments collected from the down‐hole locations.An increase in magnetic remanence carried in the coarse soil fraction was found to consistently and reliably distinguish those soils associated with human occupation. Investigations into the origin of the magnetic signature have suggested this remanence resides in nodules of burnt clay found in the archaeological soils. As it is suspected that domestic fires produced these clay aggregations, this phenomenon may extend to a wide range of sites and thus provide a technique for buried site identification that is broadly applicable. Copyright © 2006 John Wiley & Sons, Ltd.

Potencialidades de um caulim calcinado como material de substituição parcial do cimento portland em argamassas

A utilização de argilas calcinadas na forma de metacaulinita, como material pozolânico para argamassas e concretos, tem recebido atenção considerável nos últimos anos. Este trabalho objetivou avaliar o desempenho mecânico de argamassas, nas quais foi utilizado um caulim calcinado proveniente do Estado da Paraíba, como material de substituição parcial do cimento Portland. Utilizaram-se duas finuras do caulim: passando nas peneiras ABNT 200 (0,074 mm) e 325 (0,044 mm) e calcinados nas temperaturas de 700, 800 e 900 ºC pelo tempo de 2 h. As amostras foram caracterizadas através de análise química, análise térmica diferencial, difração de raios-X e área específica. Obteve-se o índice de atividade pozolânica com a cal e o cimento Portland. O percentual de substituição adotado foi de 0, 10, 20, 30 e 40%. A relação aglomerante: areia foi de 1:1,5 e a relação água/aglomerante fixada igual 0,4. O efeito da substituição parcial do cimento na argamassa foi avaliado através da resistência à compressão simples, nas idades de 7, 28 e 90 dias. As argamassas estudadas apresentaram resistência superior em relação à da referência, até o nível de 30% de substituição.

Bronzealderens kulthuse i Thy – Anlæg med relation til gravkulten

Bronzealderens kulthuse i Thy – Anlæg med relation til gravkulten

Archaeomagnetic dating of archaeological sites from Switzerland and Bulgaria

Baked materials from three archaeological sites in Switzerland and one in Bulgaria have been examined and dated archaeomagnetically. The detailed rock-magnetic properties of the burnt clay collected have already been studied therefore and have been published elsewhere (Geophysical Journal International 153 (2003) 146). The main aim of this paper is to determine the terminus ante quem for the last firing of the clay collected from pottery kilns or burnt layers. The directional and intensity results of the ancient geomagnetic field corresponding to the time of the structure's last firing are given for each site. These geomagnetic parameters are then compared with reference curves to provide archaeomagnetic dates for the last use of the kilns. Application of archaeomagnetism as a dating tool is only possible for those regions that already have reference curves. Bulgaria is fortunate in having established reference curves covering almost the last 8000 years. Two Swiss sites were dated using only directional results on the basis of existing palaeodirectional results for Switzerland as well as the French directional reference curves. The archaeomagnetic dates of three of the sites were then compared to archaeological evidence and available radiocarbon dates. The palaeointensity data obtained from this study will enrich the existing archaeomagnetic database for western Europe.

Formulation of Some Frit Compositions for Rapid Once-Fired Wall Tile Glaze

Three frit compositions were formulated and studied by varying the major constituents—alkalis (K2O + Na2O) and alkaline earth oxide (CaO) with minor changes in ZnO, SiO2, Al2O3 and B2O3content. The frits produced were characterized with respect to fusion, flow and thermal expansion properties and compared with a frit of imported origin. It is observed that fusion and flow characteristics of the frits are strongly influenced by the combined fluxing effect of CaO and calcium borate. The thermal expansion value increases with the increase in alkali content. The performance of the frits in rapid once-fired wait tile glaze was also studied by preparing a slip made of 90 wt% frit and 10 wt% white burning clay applied on green wall tile sample and fired at 1100°C. The performance of one formulation produced in the present study was almost on a par with imported frit.

Industrial trial production of low energy belite cement

Abstract The Portland cement industry consumes large amounts of energy and produces huge quantities of carbon dioxide, which contribute to global warming, the so-called “Greenhouse Effect”. Industrial trials are reported for the production of belite cements (≈3000 t) at lower temperatures and with lower lime saturation factors than for ordinary Portland cement. Belite cements with reasonably good properties have been made on an industrial scale from limestone, burnt clay, volcanic ash, pyrite ash and gypsum. A rapid rate of cooling improves the hydraulic activity, and also the physical–mechanical properties by stabilising reactive forms of belite. Such low energy cements provide a cheap alternative to Portland cement with properties that are acceptable for many applications and the additional benefit of possible improved durability.

Studies in organic archaeometry IV: analysis of an organic agglutinant used to fix iron-age clay figurines to their base

Among many other objects a number of (mainly broken) figurines made of burnt clay were found in a richly furnished Early Iron-age tomb excavated in Lower Austria. Some of these had a dark organic material on their legs, obviously intended to fix the figurines to a base. A small sample of this agglutinant was analyzed: upon isolation of the characteristic terpenecontaining fraction C-nmr spectroscopy showed considerable quantities of betulin. Thus this adhesive can be considered as birch bark pitch.